Swivel-mounted grapple apparatus with damping action

ABSTRACT

A grapple mechanism is suspended in a pendulous manner from the free end of a boom. To prevent free swinging, one vane member is associated with the grapple mechanism so as to move therewith. This vane, together with a stationary vane, project into a chamber or compartment containing a liquid having a desired viscosity to provide resistance to the movement of the vane associated with the grapple mechanism and thereby provide the damping action.

United States Patent Inventor John P. Lnndberg Washhurn, Wis. 814,616

Apr. 9, 1969 July 13, 1971 Belolt Corporation Belolt, Wis.

Appl. No. Filed Patented Assignee SWIVEL-MOUNTED GRAPPLE APPARATUS WITH DAMPING ACTION 7 Claims, 3 Drawing Figs.

11.8. CI. 294/86 R, 294/88 int. Cl B661: 1/00 188/93;

[56] References Cited UNITED STATES PATENTS 3,363,929 1/1968 Nelson... 294/106X 3,420,548 1/1969 Wakeman 188/93 X Primary Examiner-Harvey C. Hornsby Assistant Examiner-Douglas D. Watts Attorney-Bugger, Peterson, Johnson and Westman ABSTRACT: A grapple mechanism is suspended in a pendulous manner from the free end of a boom. To prevent free swinging, one vane member is associated with the grapple mechanism so as to move therewith. This vane, together with a stationary vane, project into a chamber or compartment containing a liquid having a desired viscosity to provide resistance to the movement of the vane associated with the grapple mechanism and thereby provide the damping action.

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v A a 3 3; *s\30 PATENTEU JUL] 3 Ian INVIJN'I 01. JOHN P.LUNDBERG mp {MA/Ml ATTORNEYS SWIVEL-MOUNTED GRAPPLE APPARATUS WITH DAMPING ACTION BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates generally to grapple mechanisms for loading logs and the like, and pertains more particularly to apparatus for providing a damping action to eliminate the free swinging of the grapple mechanism.

2. Description of the Prior Art In conducting logging operations, particularly those concerned with the handling or loading of pulpwood, it is customary to mount a grapple mechanism at the free end of an articulated boom assembly. The boom assembly in turn is rotatively mounted on a platform so that it can be oriented or swung in various angular directions in order to pick up the logs or bolts laying on the ground. It is, of course, quite difficult to ick up the logs at their true center of gravity. Hence, the logs will tend to tilt the grapple mechanism. When the logs are released or dropped, the grapple mechanism, by virtue of its pivotal suspension, will oscillate. Also, even when the grapple mechanism is empty, the abrupt stopping and starting of the swing platform asfar as its rotation is concerned will initiate a swinging action that has proved troublesome in the past.

Accordingly, one object of the present invention is to minimize the oscillatory action that has heretofore been present. More specifically, an aim of the invention is to provide a desired degree of damping action by virtue of two vanes, one of which is movable in a camber containing hydraulic fluid and increases the differential pressure existing in said chamber by reason of its coaction with a stationary vane.

Another object of the invention is to provide damping ac tion that is in a particular direction so as to enhance the utility thereof as far as log loading operations are concerned. In this regard, it is common to employ universal joints for suspending the grapple mechanism from the free end of the boom assembly. The oscillatory motion that is objectionable is in one direction and the present invention minimizes the swinging of the grapple in an arc that is objectionable, permitting the grapple mechanism to swing in a direction which is not troublesome.

A further object of the invention is to provide apparatus for minimizing the swinging movement of a grapple mechanism which lends itself readily to attachment to existing equipment.

Actually, the envisaged apparatus is so compact that it presents virtually no problem as far as incorporating it into, and using it with, existing equipment.

Yet another object of the invention is to provide apparatus of the foregoing character that is relatively inexpensive to manufacture, thereby encouraging its widespread use as far as relatively small logging operators are concerned.

Briefly, the present invention makes use of two vanes, one of which is associated with the grapple mechanism so as to move in unison therewith, and the other of which vane is held in a fixed relationship. By reason of the movement of the grapple-associated vane, the confined liquid is forced through orifices formed in the movable vane so as to provide the resistance that militates against the swinging of the grapple mechanism. Thus, a differential pressure is created within the hydraulic chamber and the fluid contained therein is forced against one side of the stationary vane when the movable vane is rotated in one direction and the opposite side of said stationary vane when the movable vane rotates in the opposite direction.

BRIEF DESCRIPTION OF THE DRAWING FIG. I is a side elevational view illustrating my invention in :onjunction with a typical grapple mechanism that is suspended from the free end of a boom which has been delICtELI only fragmentarily;

FIG. 2 is a view resembling FIG. I but on an enlarged scale, portions thereof being broken away so as to illustrate the construction of the apparatus; and

FIG. 3 is a sectional view taken in the direction of line 3-3 of FIG. 2. M

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring first to FIG. 1, the conventional grapple mechanism appearing in this figure has been denoted generally by the reference numeral 10. The grapple mechanism includes a frame or head 12, a plurality of cooperable jaws 14 pivotally mounted to the head by virtue of a pair of pins 16. Hydraulic motors in the form of two rams actuate the jaws into open and closed positions about the pivot pins 16. As is obvious from FIG. I, the rams 18 have actuated the jaws 14 into their closed or grappling position. To effect the opening and closing ofthe jaws 14, additional pins 20 c0nnect the rods (not visible) to the jaws. Similarly, pins 22 connect the closed end of the cylinder of the rams 18 to the head 12. Extending upwardly from the head 12 is an integral collar 24 having a tubular end 25 (FIGS. 2 and 3) of slightly reduced cross section, the tubular end 25 having a pair of diametrically aligned holes 26 for a purpose presently to be explained.

A joint unit embodying my invention has been labeled 28, being comprised of a lower yoke member 30 and an upper yoke member 32. The lower yoke member 30 will now be 1 described in detail. In this regard, it will be observed that the member 30 includes a sleeve 34 having an internal shoulder 36 and aligned holes 38 which are registrable with the previously mentioned aligned holes 26. By virtue of a transverse pin 40, it will be appreciated that when the tubular end 25 is inserted within the sleeve 34 to the degree necessary to effect registration of the holes 38 with the holes 26, the pin 40 can be passed through these registered holes.

The yoke member 30 additionally includes a horizontally disposed cylindrical casing or housing 42 that is welded to the upper end of the sleeve 34 at locations 44. The cylindrical casing 42 has a centrally disposed bore or small diameter portion 46, an intermediate diameter portion 48 at each end of the smaller diameter portion 46 and a large diameter portion 50 adjacent the ends of the cylindrical casing 42. The reason for this stepped or shouldered configuration will be described hereinafter.

At this time, attention is directed to two radial passages 52 that are drilled through the upper segment of the cylindrical casing 42 for the accommodation of a pair of bolts 54. The bolts extend downwardly through the passages 52 into engagement with a vane 56, the vane 56 having a pair of threaded apertures 58 for the reception of said bolts 54. It will be appreciated that the vane 56 is attached or held in a fixed relationship with the cylinder 42 through the agency of the bolts 54.

Passing now to a description of the upper yoke member 32, it will be seen that this bifurcated member has a pair of paral lel legs 60 which are laterally spaced so as to receive therebetween the cylindrical casing 42 belonging to the lower yoke member 30. The parallel legs 60 are formed with aligned holes 62. Before mentioning the function of the holes 62, it will be discerned that a lug 64 having a bottom horizontal flap at 66 is integral with the leg 60 residing at the left as viewed in FIG. 2. The aligned holes 62 receive a shaft 68 provided with a square head 70 having an upper flat 72. It will be understood that the two flats 66, 72 coact with each other so as to prevent rotation of the shaft 68. The shaft 68 has a threaded end 74 and a nut 76 is mounted thereon, there being a washer 78 disposed between the nut 76 and the particular leg 60 that is located at the right in FIG. 2.

Shown only in phantom outline in FIG. 2 is a keyway 80, although the keyway is visible in solid outline in FIG. 3 due to the plane in which the sectional view constituting FIG. 3 is taken as far as FIG. 2 is concerned. The keyway 60 receives the upper edge of a second vane 84, the vane 84 having several orifices 86 formed therein. It can be pointed out at this time, that the vane 04- is a stationary vane, the previously mentioned vane 56 being the movable or rotatable one due to its association with the cylindrical casing 42 that is in turn associated with the grapple mechanism 10.

To provide for the relative movement of the vane 56 with respect to the vane 84, a bearing means is incorporated into the interior of the cylindrical casing 42. In this regard, a bushing 88 has a bore 90 extending therethrough which loosely encircles the shaft 68. The bushing 88 has a small outer diameter portion 92 which contains a slot 94 through which the vane 84 extends. The small diameter portion 42 extends to the right as viewed in FIG. 2 until it reaches what will be termed an annular wall or shoulder 95. The wall 95 extends radially outwardly and then forms an intermediate diameter portion 96 that extends to the right and then outwardly to provide a large diameter portion or flange 98.

An end cap 102 has a small diameter portion 104 and extending inwardly from the small diameter portion 104 is a wall 105. There is also a large diameter portion 106 on the end cap 102 that forms a flange 108. From FIG. 2 it will also be perceived that there is an internal groove 110 formed in the end cap 102 and the purpose of this groove will be described shortly.

At this time, the means for holding the cap 102 in place will be described. In this regard, a circumferential groove 112 is formed in the shaft 60 and receives therein a retaining ring 114. Thus, the cap 102 is prevented from moving to the left as viewed in FIG. 2 through the agency of the ring 114. A pair of O rings 116 are located adjacent the flanges 98 and 108, both of these sealing members being of the same size. A smaller ring 118 is disposed in the above-mentioned internal groove 110.

Having referred to the several O-rings 116, 118, it will be well at this time to mention the existence of a chamber or compartment 112 for containing liquid having a desired viscosity. The chamber 120 is formed by the cylindrical surface constituting the small diameter portion 92 of the bushing 88, the annular wall 92, the annular wall 105 and the central bore 46 of the cylindrical casing 42. It is into this chamber 120 that the two vanes 56, 04 project.

The upper end portion of the yoke member 32 is provided with a bore 122 that receives therein a knuckle pin 124. The knuckle pin 124 is carried at the free end ofa boom assembly 126, only a fragmentary portion thereof being illustrated. The boom assembly 126 includes a pair of laterally spaced strips 128, each having a hole 130 for the accommodation of the pin 124.

As far as the operation of my apparatus is concerned, it is quite simple. In this regard, it will be recognized that the vane 56, owing to its fixed attachment to the cylindrical casing 42 moves in unison with the grapple mechanism when the grapple mechanism tends to swing about the shaft 6%}. It will be recalled that the shaft 68 is prevented from rotation by virtue of the square head 70 thereon, more specifically the presence of the flat 72 that is prevented from rotating due to the flat 68 thereabove which is a portion of the lug 64. Since the vane 84 is retained in the keyway 30 of the shaft 68, it cannot rotate since the shaft 68 cannot rotate.

What transpires is better seen from an inspection of FIG 3. If the grapple mechanism 10 rotates in a clockwise direction about the shaft 68, the bushing 88 serving as a bearing, the vane 56 moves from its twelve oclock position. This creates a pressure differential because the liquid confined between the vane 56 and the vane 84, more specifically the fluid between the right side of the vane 56 and the right side of the vane 84, will be forced against the stationary vane 84. While some leakage can occur between the vane 84 and the bore 46, the main avenue of flow is through the orifices 86. Hence, as the grapple mechanism 10 swings in a clockwise direction the entrapped fluid is forced through the orifices 86 and the liquid in this way provides considerable resistance to the swinging movement ofthe grapple mechanism 10.

On the other hand, if the rotation of the grapple 10 about the shaft 68 is in a counterclockwise direction, the action takes place on the other side of the vanes, the left side of the vane 56 under these circumstances forcing the liquid through the orifices 86 from the left side of the vane 84.

From the description herein given, it should be readily apparent that a damping action is provided by the two vanes 56 and 84. Normally, the amount of resistance that is to be provided will be known in advance, it will be recognized that the specific viscosity of the hydraulic liquid contained in the chamber will influence the rate at which the damping occurs. If the liquid is quite viscous, more damping will be derived then when a less viscous fluid is employed. Likewise, the size or cross section of the various orifices will determine the amount of damping action for a given liquid.

One important aspect of the situation is that in the handling and loading of logs, there is a particular axis about which the damping is to be achieved. This axis is the axis provided by the shaft 68. The axis provided by the pin 124, as far as the picking up of logs is concerned, is relatively unimportant. Consequently, a true universal joint is provided when the axes furnished by the shaft 68 and the pin 124 are taken into account, yet the particular axis that is most critical is adequately used when practicing the teachings of the instant invention.

lclaim:

1. Swivel-mounted grapple apparatus with damping action for minimizing'the delay time between the dropping or unloading of one elongated load and the picking up or loading of the next load comprising a grapple mechanism including a head, a pair of jaws pivotally mounted at their upper ends to said head and ram means connected between said head and jaws for actuating said jaws into open and closed positions, lower and upper yoke members, means connecting said yoke members together for pivotal movement about a generally horizontal axis, means forming a chamber between portions of said yoke members for containing liquid having a desired viscosity, a pair of vanes projecting into said chamber, one vane being fixedly connected to said lower yoke member and the other vane fixedly connected to said upper yoke member, means attaching said grapple mechanism to said lower yoke member, and means for connecting said upper yoke member to a boom element for pivotal movement about a second generally horizontal axis above said first generally horizontal axis, said second axis being transverse to said boom element so that said grapple mechanism is free to pivot in the same vertical plane containing said boom element and said first axis extending generally at right angles to said second axis at an elevation therebelow so that said lower yoke member and said grapple mechanism gravitationally depend therefrom, whereby swinging movement of said grapple mechanism about said first axis to either side of the vertical plane containing said boom element is resisted by the resistance provided by said liquid to produce the damping action and thereby reduce as a result of said damping action the delay time between unloading and loading.

2. Swivel-mounted grapple apparatus in accordance with claim 1 in which one of said vanes has at least one orifice formed therein through which liquid can pass during relative movement of said vanes.

3. Swivel-mounted grapple apparatus in accordance with claim 1 in which said means pivotally connecting said yoke members together includes a shaft extending through both yoke members, said shaft having a head thereon provided with a flat surface, said upper yoke member having a lug projecting therefrom and overlying said flat surface to prevent said shaft from rotating, one of said vanes being fixedly disposed with respect to said shaft, and said lower yoke member having at its upper end a cylindrical casing fixedly attached thereto, said cylindrical casing having the other of said vanes fixedly disposed thereon, and said chamber being angularly situated between said sleeve and said cylindrical casing.

4. Swivel-mounted grapple apparatus with damping action comprising a grapple mechanism, a first yoke member extending upwardly from said grapple mechanism and having a cylindrical upper end, a second yoke member attachable to one end of a boom and having a pair of parallel legs laterally spaced for the accommodation therebetween of said cylindrical casing, said legs having aligned apertures therein, a shaft received in said aligned apertures and extending through said cylindrical casing, bearing means interposed between said shaft and said cylindrical casing, means forming a chamber for containing a liquid having a desired viscosity, a first vane fixedly located with respect to said shaft and a second vane fixedly located with respect to said cylindrical casing, said vanes projecting into said chamber, whereby relative movement of said vanes produces said damping action by means of the resistance to movement by the liquid contained in said chamber.

5. Swivel-mounted grapple apparatus in accordance with claim 4, in which said shaft is formed with a head having at least one flat thereon, and said second yoke member has a lug thereon engageable with said flat so as to prevent rotation of said shaft.

6. Swivel-mounted grapple apparatus in accordance with claim 4, in which said bearing means includes a sleeve member having a first portion of one diameter and a second portion of a larger diameter, said portion of larger diameter forming one wall of said chamber and said chamber residing angularly between said one diameter portion and the bore of said cylindrical casing, and cap means providing an opposite wall for said chamber, said cap means fitting between said one diameter portion of said sleeve member and the bore of said cylindrical casing.

7. Swivel-mounted grapple apparatus with damping action comprising a grapple mechanism, lower and upper yoke members, means including a shaft extending through both of said yoke members for connecting said yoke members together for pivotal movement about a generally horizontal axis, said shaft having a head thereon provided with a flat surface, said upper yoke member having a lug projecting therefrom and overlying said flat surface to prevent said shaft from rotating, means forming a chamber between portions of said yoke members for containing liquid having a desired viscosity, a pair of vanes projecting into said chamber, one of said vanes being fixedly disposed with respect to said shaft, and said lower yoke member having at its upper end a cylindrical casing fixedly attached thereto, said cylindrical casing having the other of said vanes fixedly disposed thereon, said chamber being annularly situated between said sleeve and said cylindrical casing,

shoulder means at one end of said cylindrical casing, comple-- mental flange means at one end of said sleeve member engaging said shoulder means, shoulder means at the other end of said cylindrical casing, a cap member received in the shoulder means at said other end for closing said other end of said cylindrical casing, said cap member forming one side of said chamber, means attaching said grapple mechanism to said lower yoke member, and means for connecting said upper yoke member to the boom element so that said lower yoke member and said grapple mechanism gravitationally depend therefrom, whereby swinging movement of said grapple mechanism is resisted by the resistance provided by said liquid to produce the damping action. 

1. Swivel-mounted grapple apparatus with damping action for minimizing the delay time between the dropping or unloading of one elongated load and the picking up or loading of the next load comprising a grapple mechanism including a head, a pair of jaws pivotally mounted at their upper ends to said head and ram means connected between said head and jaws for actuating said jaws into open and closed positions, lower and upper yoke members, means connecting said yoke members together for pivotal movement about a generally horizontal axis, means forming a chamber between portions of said yoke members for containing liquid having a desired viscosity, a pair of vanes projecting into said chamber, one vane being fixedly connected to said lower yoke member and the other vane fixedly connected to said upper yoke member, means attaching said grapple mechanism to said lower yoke member, and means for connecting said upper yoke member to a boom element for pivotal movement about a second generally horizontal axis above said first generally horizontal axis, said second axis being transverse to said boom element so that said grapple mechanism is free to pivot in the same vertical plane containing said boom element and said first axis extending generally at right angles to said second axis at an elevation therebelow so that said lower yoke member and said grapple mechanism gravitationally depend therefrom, whereby swinging movement of said grapple mechanism about said first axis to either side of the verTical plane containing said boom element is resisted by the resistance provided by said liquid to produce the damping action and thereby reduce as a result of said damping action the delay time between unloading and loading.
 2. Swivel-mounted grapple apparatus in accordance with claim 1 in which one of said vanes has at least one orifice formed therein through which liquid can pass during relative movement of said vanes.
 3. Swivel-mounted grapple apparatus in accordance with claim 1 in which said means pivotally connecting said yoke members together includes a shaft extending through both yoke members, said shaft having a head thereon provided with a flat surface, said upper yoke member having a lug projecting therefrom and overlying said flat surface to prevent said shaft from rotating, one of said vanes being fixedly disposed with respect to said shaft, and said lower yoke member having at its upper end a cylindrical casing fixedly attached thereto, said cylindrical casing having the other of said vanes fixedly disposed thereon, and said chamber being angularly situated between said sleeve and said cylindrical casing.
 4. Swivel-mounted grapple apparatus with damping action comprising a grapple mechanism, a first yoke member extending upwardly from said grapple mechanism and having a cylindrical upper end, a second yoke member attachable to one end of a boom and having a pair of parallel legs laterally spaced for the accommodation therebetween of said cylindrical casing, said legs having aligned apertures therein, a shaft received in said aligned apertures and extending through said cylindrical casing, bearing means interposed between said shaft and said cylindrical casing, means forming a chamber for containing a liquid having a desired viscosity, a first vane fixedly located with respect to said shaft and a second vane fixedly located with respect to said cylindrical casing, said vanes projecting into said chamber, whereby relative movement of said vanes produces said damping action by means of the resistance to movement by the liquid contained in said chamber.
 5. Swivel-mounted grapple apparatus in accordance with claim 4, in which said shaft is formed with a head having at least one flat thereon, and said second yoke member has a lug thereon engageable with said flat so as to prevent rotation of said shaft.
 6. Swivel-mounted grapple apparatus in accordance with claim 4, in which said bearing means includes a sleeve member having a first portion of one diameter and a second portion of a larger diameter, said portion of larger diameter forming one wall of said chamber and said chamber residing angularly between said one diameter portion and the bore of said cylindrical casing, and cap means providing an opposite wall for said chamber, said cap means fitting between said one diameter portion of said sleeve member and the bore of said cylindrical casing.
 7. Swivel-mounted grapple apparatus with damping action comprising a grapple mechanism, lower and upper yoke members, means including a shaft extending through both of said yoke members for connecting said yoke members together for pivotal movement about a generally horizontal axis, said shaft having a head thereon provided with a flat surface, said upper yoke member having a lug projecting therefrom and overlying said flat surface to prevent said shaft from rotating, means forming a chamber between portions of said yoke members for containing liquid having a desired viscosity, a pair of vanes projecting into said chamber, one of said vanes being fixedly disposed with respect to said shaft, and said lower yoke member having at its upper end a cylindrical casing fixedly attached thereto, said cylindrical casing having the other of said vanes fixedly disposed thereon, said chamber being annularly situated between said sleeve and said cylindrical casing, shoulder means at one end of said cylindrical casing, complemental flange means at one end of said sleeve member engaging said shoulder means, Shoulder means at the other end of said cylindrical casing, a cap member received in the shoulder means at said other end for closing said other end of said cylindrical casing, said cap member forming one side of said chamber, means attaching said grapple mechanism to said lower yoke member, and means for connecting said upper yoke member to the boom element so that said lower yoke member and said grapple mechanism gravitationally depend therefrom, whereby swinging movement of said grapple mechanism is resisted by the resistance provided by said liquid to produce the damping action. 